Characterization and modelling of pre-gelation/gelation behaviour of polymer composites

聚合物基复合材料最终成为航空航天领域的重要材料：波音787、空中客车A350、庞巴迪C系列都严重依赖这些材料。 同样，复合材料在风能领域的应用也很重要，而在汽车领域，复合材料的应用也有重大进展，以宝马i3和i8系列为首。 在所有情况下，尽可能快速有效地可靠制造复杂结构，同时控制工艺质量的能力至关重要。 * 工艺模拟（现在包括在集成计算材料工程或多尺度建模中）很早就被提出作为降低风险和优化复合材料加工的方法。 模拟对于复合材料一直很有吸引力，因为材料和结构基本上是同时制造的;因此，当面对真实的零件和几何形状时，问题的复杂性会迅速增加。该提案旨在从根本上了解下一代复合材料的制造科学，以实现更新，更快，更便宜，更可持续和更环保的工艺，包括增材制造。拟议工作的首要目标是开发一个连贯和连续的描述的机械行为（a）热固性树脂从未固化到固化状态，在一个温度范围内采取的材料行为从玻璃到橡胶（和流体，如果预凝胶化）。 感兴趣的行为包括粘性和粘弹性响应（粘度、储存模量和损耗模量）以及表面张力、固化收缩和热膨胀效应;和（B）由这种树脂制成的预浸料，包括初始纤维波纹度（来自成网工艺）的效应以及材料在预胶凝状态下起皱的能力。 材料响应的描述应该是相容本构方程的基础，相容本构方程描述了在这种广泛的条件下的材料响应。 这将是对现有技术的一个重大进步，在现有技术中，材料特性的表征是以脱节和分散的方式进行的，并且做出了主要假设。目前使用的第一代材料表征的好处是第一代工艺模拟的残余应力和尺寸变化越来越明显。 通过本提案中设想的基础工作，我们将扩大和深化基础树脂和预浸料行为的基本表征和表现，这些基本表征和表现将在未来几十年内引起重大兴趣。 只有有了坚实的科学基础，先进制造才能成为现实。

Polymer matrix composite materials have finally become significant materials in aerospace: the Boeing 787, Airbus A350, Bombardier C-Series all depend heavily on these materials. Likewise, the use of composites in the wind energy sector is now significant, and there is a major move to composites in automotive, led by BMW with their i3 and i8 series. In all cases, the ability to reliably manufacture complex structures as quickly and efficiently as possible yet control the quality of the process is critical. ***Process simulation (nowadays included in Integrated Computational Materials Engineering or Multi-Scale Modelling) was proposed very early on as a method to reduce risk and optimize processing of composites. Simulation has always been attractive for composites as the material and structure are essentially made at the same time; thus the complexity of the problem scales rapidly when faced with real parts and geometries.***This proposal is for fundamental understanding of manufacturing science of next generation composites for newer, faster, cheaper, more sustainable and greener processes including additive manufacturing.***The overarching objective of the proposed work is to develop a coherent and continuous description of the mechanical behaviour of (a) a thermoset resin from the uncured to the cured state, over a range of temperatures taking the material behaviour from glassy to rubbery (and fluid if pre-gelation). The behaviour of interest includes the viscous and viscoelastic response (viscosity, storage and loss moduli) as well as surface tension, cure shrinkage, and thermal expansion effects; and (b) a prepreg made of such resin, including the effect of initial fibre waviness (from the prepregging process) as well as the ability of the material to wrinkle in the pre-gelation state. The description of the material response should be the basis of compatible constitutive equations that describe the material response over this wide range of conditions. This will be a major advance on the current state of the art where the characterization of material properties has been done in a disjointed and scatter-shot manner, and major assumptions made.***The benefits of currently used first generation characterization of materials for first generation process simulations of residual stress and dimensional change are increasingly obvious. With the fundamental work envisaged in this proposal, we will broaden and deepen the fundamental characterization and representation of basic resin and prepreg behaviour over the range of materials and processes that will be of significant interest in the next decades. Only with a solid science base can advanced manufacturing become a reality.